Field of the Invention
The present invention relates to a control method of a hybrid vehicle. More particularly, the present invention relates to a control method of a hybrid vehicle for improving fuel efficiency and reducing time for clutch engagement during conversion into an HEV mode from an EV mode according to driver's acceleration will.
Description of Related Art
A hybrid vehicle is a vehicle using two or more power sources and generally refers to a hybrid electric vehicle driven using an engine and a motor. A hybrid electric vehicle may form various structures using two or more power sources including an engine and a motor.
In general, a hybrid electric vehicle uses a power train in a manner of a transmission mounted electronic device (TMED) in which a motor, and a transmission and drive shaft are connected in series to each other.
In addition, a clutch is disposed between an engine and a motor. According to whether the clutch is engaged, the hybrid electric vehicle is driven in an electric vehicle (EV) mode or in a hybrid electric vehicle (HEV) mode.
The EV mode is a mode in which a vehicle is driven by only driving torque of a motor. The HEV mode is a mode in which the vehicle is driven by driving torque of the motor and the engine.
Upon being converted into the HEV mode from the EV mode, the hybrid vehicle synchronizes engine torque with motor torque and then engages a clutch. Synchronization of engine torque with motor torque is referred to as torque blending.
However, according to conventional art, during conversion into an HEV mode from an EV mode, engine speed is synchronized with motor speed while an engine is zero-torque controlled for a predetermined period of time and the clutch is engaged. Accordingly, problems arise in that impact is applied to the clutch according to engine torque and torque blending time for synchronization of engine torque with motor torque is lengthened.
In addition, since the engine is zero-torque controlled for a predetermined period of time, problems arise in that fuel efficiency of the vehicle is degraded.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.